Spark-plug



J. W. NELSON.

SPARK'PL APPLICATION FILED MAR. 19, 1919.

Patented Apr. 26, 1921 JOHN WM. NELSON, OF NORWOOD, MASSACHUSETTS.

SPARK-PLUG.

Application riled March 19, 1919. Serial No. 283,463.

To all whom it may concern:

Be it known that 1, JOHN VVILLIAM NELSON, a citizen of the UnitedStates, residing at Norwood, in the county of Norfolk and State ofMassachusetts, have invented certain new and useful Improvements inSpark-Plugs; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and usethe'same.

This invention relates to improvements in spark plugs and has for one ofits objects the provision of a device of this character whereby theaccumulation of carbon between the insulator, electrodes and body of thedevice is entirely obviated, thus preventing short circuiting of thespark plug.

Another object of this invention is the provision of means whereby theinsulator and electrodes can be simultaneously removed from the body forcleaning without removing the body from the engine.

A further object of this invention is the provision of a spark plug ofthe above stated character, which shall be simple, durable, andefficient, and which may be manufactured and sold at a comparatively lowcost.

With these and other objects in view as will become more apparent as thedescription proceeds, the invention consists in certain novel featuresof construction, combination and arrangement of parts as will behereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had tothe following description and accompanying drawings, in which Figure 1is a side elevation of a spark plug constructed in accordance with myinvention,

Fig. 2 is a vertical sectional View of the same,

Fig. 3 is a side elevation of the insulator,

Fig. 4 is a vertical sectional view of the securing collar, and

Fig. 5 is a side elevation of a sleeve.

Fig. 6 is a similar view illustrating a nut.

Referring in detail to the drawing, the numeral 1 indicates as anentirety a spark plug including a body 2 having a threaded portion 3adapted to be threaded into the usual spark receiving opening of anengine, (not shown). The body 2 has formed thereon an enlarged portionprovided with wrench engaging faces 1 whereby the extension 3 can bereadily threaded into the openlng 'of the engine. An annular flange 5 isformed upon the body 2 between the wfench engaging faces 4 and thethreaded extension tains the sleeve 6 in the body by bearing against anannular flange formed on theinner end ofsaid sleeve. The upper end ofthe sleeve 6 projects above the body and nut and is screw threaded toreceive a securing cap 8. The cap 8 is provided with a knurled face andhas formed upon its upper end an inwardly directed annular flange 9. Thecap 8 is internally screw threaded for cooperation with the screwthreads upon the up er end of the sleeve.

n insulator 10 constructed from porcelain or any other material suitablefor the purpose extends through the sleeve 6 and body 2, having itslower end flush with the lower edge of the screw threaded extension 3 ofthe body 2 so as to prevent accumulation of carbon between the insulatorand the body 2. The insulator 10 has extending therethrough a centralelectrode 11, having its lower end projecting beyond the lower end ofthe insulator while its opposite end projects beyond the upper end ofthe electrode and is screw threaded to receive the usual terminalsecuring nut 12. An electrode 13 is carried by the insulator 10 and hasits lower end projecting beyond the lower end of the insulator and bentin hook formation which has its free end spaced from the electrode .11to form the spark,

gap. The electrode 13 extends upwardly and outwardly through the wall ofthe insulator 10 for engagement with the inner face of the sleeve 6 soas to ground the same to the body of the spark plug. A flange 14 isformed upon the insulator 10 adjacent its upper end, and is providedwith an inclined lower face 15 for engagement with the upper edge of thesleeve 6 and is provided with an upper straight face 16 to beengaged bythe annular flange 9 when the securing cap 8 is threaded on to the upperend of the sleeve 6 to establish an airtight connection between thesleeve and the insulator.

From the foregoing description taken in connection With the accompanyingdrawings, it will be noted that it is only necessary to remove the cap 8in order to remove both the insulator and the electrodes 11 and 13simultaneously, thus permitting of the body 2, to remain in the engine.

While I have shown and described the preferred embodiment of myinvention, it will be understood that minor changes in construction,combination, and arrangement of parts, ma be made Without departing fromthe spirlt and scope of the invention as claimed.

Having thus described my invention, what I claim is A spark plugcomprising a body, a sleeve detachably secured in said body andprojecting beyondthe outer end thereof, an insulator extending throughthe sleeve into the body and terminating in substantially the same planewith the inner end of said body and fully closing the inner end of thebody, the outer end of the insulator pro- 7 lator in the body andsleeve, a central electrode extending through the insulator, a secondelectrode embedded in said insulator and having one end spaced from thecentral electrode to form a spark gap and itsother end extending throughthe side face of the insulator and disposed angularly and against thesleeve.

In testimon whereof I aflix my signature in presence or two witnesses.

JOHN WM. NELSON.

Witnesses:

ROYAL J. COLMAN, DAVID SCBIEHI.

